1. Field of the Invention
The present invention relates to a chassis structure constituted by a combination of a chassis member having a receiving portion and a case member having a contact surface portion mounted on the receiving portion, and an electronic apparatus including the chassis structure. In particular, the present invention relates to a chassis structure and an electronic apparatus in which, when an external force is applied to the chassis member or the case member, the external force applied to one member is received by the other member, deformation of each member can be prevented or suppressed, and the leak of unnecessary radiation (electromagnetic waves) can be reduced.
2. Description of the Related Art
Generally, an electronic apparatus includes an electronic apparatus main body having a main function of the electronic apparatus, and the electronic apparatus main body is supported by a chassis structure having a suitable configuration.
For example, a chassis structure of an electronic apparatus such as a DVD player and a terrestrial digital tuner of a TV is configured to include a metal frame on which the electronic apparatus main body is mounted, a panel which is attached to the metal frame and covers the entire electronic apparatus main body, and the like. In recent years, this type of electronic apparatus is produced so as to have a light-weight from the viewpoint of reduction of transportation cost to be paid by a user, ease of installation when starting to use, and the like. To reduce the cost of an electronic apparatus, reducing the amount of materials to be used is effective. Because of the above reasons, the plate thickness of a frame and a panel of an electronic apparatus is reduced, and hence the strength of the frame and the panel decreases. To prevent or suppress the decrease in the strength due to the reduction of the plate thickness, generally, many ideas regarding, for example, how to fold the frame and the panel or how to form a rib have been implemented. However, the decrease in strength due to the reduction of plate thickness can only be suppressed to a certain degree.
In the related art, as a chassis structure of this type of electronic apparatus, for example, there is a chassis structure described in Registered Utility Model Publication No. 3095551 (Utility Model Application No. 2003-363). In Registered Utility Model Publication No. 3095551, there is a description related to a shield structure of a disk apparatus in which unnecessary radiation of electromagnetic waves from the disk apparatus reproducing an optical disk is reduced, and electromagnetic interference is prevented.
The shield structure of the disk apparatus related to Registered Utility Model Publication No. 3095551 is configured to include a housing, a disk drive apparatus, a clamp holder, and a leaf spring. The housing of the disk apparatus includes a front panel made of resin, a back panel made of metal, an upper case made of metal, and a lower case made of metal. The disk drive apparatus is mounted on the center portion of the lower case of the housing, and a clamp holder made of metal having a substantially squared U-shape in cross section is attached to a position near the front panel in a space under the disk drive apparatus. The clamp holder and one end of the leaf spring are fixed together to the housing by a screw, and the other end of the leaf spring is in contact with the upper case, so that the clamp holder and the upper case are electrically connected by the leaf spring.
According to the shield structure of Registered Utility Model Publication No. 3095551, it is possible to electrically connect the clamp holder and the upper case and shield a connection cable with the clamp holder made of metal and the lower case made of metal. Therefore, an effect is expected in which unnecessary radiation of electromagnetic waves from a disk apparatus to which a front loading type disk drive apparatus is mounted and a front panel made of resin is attached is reduced, and electromagnetic interference to other electronic apparatuses is prevented.
However, in the shield structure of the disk apparatus described in Registered Utility Model Publication No. 3095551, there is a problem as described below. The problem in the related art will be described with reference to FIGS. 11A to 11C and FIGS. 12A and 12B. In FIGS. 11A to 11C, reference numeral 1 denotes a front frame made of metal, and a receiving portion 1a formed by folding and bending in a predetermined width in a horizontal direction is provided in an upper part of the front frame 1. A contact surface portion 2a provided at the top edge of the upper case 2 made of metal is mounted on the upper surface of the receiving portion 1a. The front frame 1 and the upper case 2 are fixed to the lower case made of metal (not shown in the figures) by screws in a side portion and a rear portion which are not seen from the front.
On the other hand, a portion where the receiving portion 1a of the front frame 1 and the contact surface portion 2a of the upper case 2 are in contact with each other is a portion located in an upper front area which is easy to see, and hence the receiving portion 1a and the contact surface portion 2a are not fixed by screws, and are simply in contact with each other. Therefore, a gap may be generated between the receiving portion 1a and the contact surface portion 2a due to variation in the accuracy with which parts are manufactured and variations in assembly operation, so that there is a problem that unnecessary radiation (especially, high-frequency electromagnetic waves) generated by the operation of the electronic apparatus main body leaks to the outside from the gap. To solve this problem, in the related art, a countermeasure in which the contact surface portion 2a is urged to the panel receiving portion 1a by using a spring member is implemented. However, there is a problem that component cost and assembly man-hours increase because an additional component such as the spring member is used.
As shown in FIG. 11A, for example, it is assumed that an external force F1 is applied downward to a front edge of the upper case 2 at the approximate center in the left-right direction. Then, as shown in FIG. 11B, the front frame 1 deforms in a bow shape by the pressing force F1 applied from the upper case to the front frame 1, and largely deforms backward in the approximate center in the left-right direction from the state shown by two-dot chain lines to the state shown by solid lines. When the amount of deformation of the front frame 1 exceeds a predetermined amount, a displacement is generated between the contact surface portion 2a of the upper case 2 and the receiving portion 1a of the front frame 1. Then, the contact surface portion 2a slips from the receiving portion 1a, sinks in front of the front frame 1, and deforms from the state shown by two-dot chain lines to the state shown by solid lines.
In FIG. 11A, for example, it is assumed that an external force F2 is applied backward toward the front frame 1 at the approximate center in the left-right direction. Then, as shown in FIG. 11C, the front frame 1 deforms backward in a bow shape by the pressing force F2, so that a phenomenon in which the front frame 1 deforms from the state shown by two-dot chain lines to the state shown by solid lines in the approximate center in the left-right direction is easily occurs.
FIGS. 12A and 12B illustrate a specific example of the problem shown in FIG. 11C. Reference numeral 3 shown in FIGS. 12A and 12B denotes, for example, a switch device such as a power switch in an electronic apparatus such as a DVD player. The switch device 3 is a tactile switch, and fixed on the front surface of the front frame 1 via a switch board 4. In such a situation, when a force beyond necessity is applied to an operation button of the switch device 3 as an operational force, a deformation occurs in the front frame 1. As a result, as shown in FIG. 12B, the front frame 1 deforms from the state shown by two-dot chain lines to the state shown by solid lines, and the operability of the operation button deteriorates.